Industrial process control and automation systems are often used to automate large and complex industrial processes. These types of control and automation systems routinely include process controllers and field devices like sensors and actuators. The process controllers typically receive measurements from the sensors and generate control signals for the actuators. In many systems, a process controller includes or is used with one or more input/output (I/O) modules, each of which can be used to provide signals to and receive signals from one or more field devices.
One popular hardware architecture for an I/O module uses a single microprocessor. During a firmware upgrade of the I/O module's microprocessor or during a reset of the I/O module's microprocessor after a firmware upgrade, the I/O module's microprocessor cannot send or receive signals. Unfortunately, this can result in a complete loss of view or control over its associated field devices. Among other problems, a non-redundant process controller that includes a single-microprocessor I/O module cannot enforce a failsafe action during a boot failure of the I/O module's microprocessor, which could occur when the microprocessor fails to boot after a firmware upgrade. As a result, part or all of an industrial process often needs to be shut down during a firmware upgrade of a process controller's I/O modules, resulting in a loss of production and the associated monetary losses. While it may be possible to incorporate multiple redundant process controllers or I/O modules in a control and automation system, this increases the complexity and cost of the overall system, and it is not always possible to have redundant process controllers or I/O modules in a system.